This application is a National Stage completion of PCT/JP2014/082592 filed Dec. 9, 2014, which claims priority from Japanese patent application serial no. 2014-116423 filed Jun. 5, 2015.
The present invention relates to a power door opening and closing device that applies assistant force to manual opening/closing operation of a door.
A power door opening and closing device used in a liftgate pivotally mounted to open and close vertically at the rear end of a vehicle body comprises an actuator that comprises a motor, a reduction mechanism for slowing down the motor and a rotary encoder for generating a pulse signal corresponding to opening/closing motion of the liftgate. An output portion of the actuator is connected to the liftgate and an operator opens and closes the liftgate manually. The rotary encoder detects opening/closing motion of the liftgate so as to start the motor and to apply an assistant force to manual opening/closing operation in JP3923704B2.
However, in the power opening device in JP3923704B2, looseness inevitably occurs at a connecting path between the actuator and the liftgate. A time delay corresponding to the looseness is generated until the rotary encoder in the actuator detects motion of the liftgate since the operator starts manual operation, so that an assistant force cannot be applied rapidly, which is a problem.
Thus, a great operating force is required at the beginning of manual operation of the liftgate, and when the assistant force is applied, catching is felt to cause discomfort in manual operation.